Valve Magazine - Winter 2011

MATERIALS Q&A

CONTINUED FROM PAGE 40

“significant” than the necks in a
forged weld-neck flange and would
exhibit quite different metallurgical
“texture” than a weld-neck flange. I
am not aware of any reported HIC fail-
ures in forged valve bonnets. Note that
proposed revision of NACE TM0284
only covers testing of blind flanges and
weld-neck flanges. It does not cover
forgings in general.

It’s up in the air whether flanged
bonnets made from carbon steel forg-
ings need to be tested. Forged bonnets
typically have “necks” much more
Many end-users and engineering,
procurement and construction contrac-
tors systematically group valves under
“piping” for material selection and
specification purposes. Because of this,
the requirement to perform HIC test-
ing on valve materials often occurs as
a result of a general piping specifica-
tion being “extended” to cover valves.
When this happens, the valve manufac-

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martensitic stainless steels.

In other words, HIC testing rarely
applies to valves. The few exceptions
would be:
turer needs to bring the situation to the
purchaser’s attention to avoid unneces-
sary testing and the associated expense
and delivery delays. VM

; Butterfly valve bodies made from carbon steel plate

; Large, fabricated valves made from carbon steel piping fittings

; Carbon steel weld-neck flanges welded to valve bodies

References:

1. NACE/ASTM Standard G193-2010, “ Standard Terminology and Acronyms Relating to Corrosion” (Houston, TX: NACE)

2. NACE Standard TM0284-2003, “ Evaluation of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced Cracking” (Houston, TX: NACE)

3. NACE Standard SP0296-2010, “Detection, Repair, and Mitigation of Cracking in Refinery Equipment in Wet H2S Environments”

(Houston, TX: NACE).

DON BUSH is a principal materials engineer at
Emerson Process Management – Fisher
( www.emersonprocess.com). Reach him at
Don.Bush@Emerson.com.

MSS Standards Are Used by PVF Professionals Every Day, All Over the World

MSS has recently published several valuable new standards including MSS SP-138,“Cleaning and Preparation of Valves and Fittings for Oxygen Service”, and MSS SP-137, “Quality Standard for Positive Material Identification of Metal Valves, Flanges, Fittings and Other Piping Components”. Current works-in-progress at MSS include standards for the modification of new valves, Silicone-free service requirements for valves, and a quality standard for pressure containing steel valve castings.